This project will develop a new microscopy instrument that is, in essence, a miniaturized fluoroscope. Living samples are placed onto a grainless fluorescent-screen, and illuminated with a laser-plasma soft x-ray source. Observation of the resultant luminescent shadow-image is accomplished using optical microscopy. The device can produce images containing three-dimensional information at a resolution that is routinely 200 nm or below. The extremely brief exposure duration of several nanoseconds results in very sharp images, even in the presence of significant specimen motility. Such capabilities will be invaluable for investigators in medical research, cell biology, microbiology, and other life sciences. Preliminary results have demonstrated the technique using a relatively large apparatus. This project will develop a much more compact device that fits directly onto a standard microscope stage, without interfering with the microscope's other imaging capabilities. Either optical microscopy, or soft x-ray microfluoroscopy can be performed in rapid succession without altering the sample environment. Phase I research will determine the practicality of the instrument by constructing a simple prototype device, and producing initial images of dry and wet samples. Phase II will develop a more advanced research tool that will be appropriately designed for subsequent commercialization. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE